In addition to backticks `command`, command substitution can be done with $(command) or “$(command)”, which I find easier to read, and allows for nesting. OUTPUT=$(ls -1) echo “${OUTPUT}” MULTILINE=$(ls \ -1) echo “${MULTILINE}” Quoting (“) does matter to preserve multi-line variable values; it is optional on the right-hand side of an assignment, as word splitting … Read more
Bash Space-Separated (e.g., –option argument) cat >/tmp/demo-space-separated.sh <<‘EOF’ #!/bin/bash POSITIONAL_ARGS=() while [[ $# -gt 0 ]]; do case $1 in -e|–extension) EXTENSION=”$2″ shift # past argument shift # past value ;; -s|–searchpath) SEARCHPATH=”$2″ shift # past argument shift # past value ;; –default) DEFAULT=YES shift # past argument ;; -*|–*) echo “Unknown option $1” exit … Read more
You can use these ANSI escape codes: Black 0;30 Dark Gray 1;30 Red 0;31 Light Red 1;31 Green 0;32 Light Green 1;32 Brown/Orange 0;33 Yellow 1;33 Blue 0;34 Light Blue 1;34 Purple 0;35 Light Purple 1;35 Cyan 0;36 Light Cyan 1;36 Light Gray 0;37 White 1;37 And then use them like this in your script: … Read more
First, get file name without the path: filename=$(basename — “$fullfile”) extension=”${filename##*.}” filename=”${filename%.*}” Alternatively, you can focus on the last “https://stackoverflow.com/” of the path instead of the ‘.’ which should work even if you have unpredictable file extensions: filename=”${fullfile##*/}” You may want to check the documentation : On the web at section “3.5.3 Shell Parameter Expansion” … Read more
You can set the internal field separator (IFS) variable, and then let it parse into an array. When this happens in a command, then the assignment to IFS only takes place to that single command’s environment (to read ). It then parses the input according to the IFS variable value into an array, which we … Read more
Answer POSIX compatible: command -v <the_command> Example use: if ! command -v <the_command> &> /dev/null then echo “<the_command> could not be found” exit fi For Bash specific environments: hash <the_command> # For regular commands. Or… type <the_command> # To check built-ins and keywords Explanation Avoid which. Not only is it an external process you’re launching … Read more
File descriptor 1 is the standard output (stdout). File descriptor 2 is the standard error (stderr). At first, 2>1 may look like a good way to redirect stderr to stdout. However, it will actually be interpreted as “redirect stderr to a file named 1“. & indicates that what follows and precedes is a file descriptor, … Read more
Use printf instead: printf “hello\nworld\n” printf behaves more consistently across different environments than echo.
You can use Marcus’s answer (* wildcards) outside a case statement, too, if you use double brackets: string=’My long string’ if [[ $string == *”My long”* ]]; then echo “It’s there!” fi Note that spaces in the needle string need to be placed between double quotes, and the * wildcards should be outside. Also note … Read more
foo=”Hello” foo=”${foo} World” echo “${foo}” > Hello World In general to concatenate two variables you can just write them one after another: a=”Hello” b=’World’ c=”${a} ${b}” echo “${c}” > Hello World